The BMW 3 Series isn't just a car. As my cohort Jonny Lieberman likes to say, the 3 Series is a segment. Now, this isn't an attempt to stoke BMW's ego, or, as many of our readers would assume, bias towards the Bavarian brand. It's just the simple truth: When an automaker chooses to compete in the luxury sports sedan segment, it's benchmarking the 3 Series. No BMW has consistently won Motor Trend comparison tests like the 3 Series has, and for good reason. The 3 Series has come to define BMW's Ultimate Driving Machine mantra and embodies the purest qualities BMW stands for as a brand.

Back in May, we hosted a sport sedan shoot-out and invited eight four-door sportboxes to duke it out. Everyone from Audi to Volvo came to play, and in the end, we said (and I quote), "This is not just a win for the 328i -- it's a massacre. ... there is no competition." Well, that was then. And then was before Cadillac had brought its new ATS to market.

Of course, Cadillac smartly realizes BMW rules the 3 Series segment, and looking over the spec sheet for the ATS, it's clear Cadillac engineers used BMW specs as they would a recipe for their grandmother's lasagna. The exterior dimensions -- length, width, and height -- are all within an inch of the 328i and the difference in curb weight is just 24 pounds (the heavier BMW has a sunroof while the ATS does not). The engine is 2.0 liters and turbocharged, just like the 328i. Output is also nearly identical, as you might expect by now: 272 hp for the ATS, 240 for the (cough, cough) underrated (cough, cough) BMW with 260 and 255 lb-ft of torque, respectively. Both cars are available with automatic gearboxes, but the Caddy gets six cogs to the BMW's eight. This being a sport sedan comparison, we decided on six-speed manuals for both cars. Wheels on both cars are 18 inches and suspension is strut front, multi-link rear on each, with anti-roll bars at both ends. Heck, even the base price of each car is an identical $35,795 with destination fees factored in.

But let's turn our attention from spec sheets to sheetmetal. For 2013, the BMW gets a subtle redesign. All that "evolutionary, not revolutionary" stuff you've been reading about the 328i is true -- BMW isn't messing too much with what works. The Bimmer's lines are taut and the stance is aggressive, with 18-inch wheels filling out the fenderwells on our Sport model. It looks lean and toned and every inch a BMW. Meanwhile, there's no doubt the ATS' sheetmetal is influenced by the CTS, but the overall design is more than a four-fifths scale take on Big Brother. We love the swoopy, Mercedes-esque beltline and the chiseled front end. Caddy didn't go overboard on the flash, keeping chrome trim subtle, and the illuminated door handle inserts and vertical headlights that sweep up the hoodline are lovely touches.

Inside, the two cars couldn't be more different. BMW sticks with an understated black interior, spiced up only with a red trim strip across the dash and red stitching on the leather seats and steering wheel. The dash is all soft-touch grained material of reasonable quality, but the matte black rubberized buttons and switchgear look a bit cheap for a car that can easily be optioned to more than $50k. Nevertheless, the latest version of iDrive works intuitively and quickly, with a well-integrated voice command system. The ATS interior is a little more flashy, with a good-looking leather-topped dash and a stylized piano black center stack that unfortunately picks up smudges and fingerprints like mad. Cadillac's CUE interface, while not on the same level as the continually refined iDrive, works well enough with some advanced touches including a proximity sensor that hides cluttering functions until a hand moves within inches of the touch screen. Buttons on the center stack incorporate haptic feedback for more positive response.

Both cars are designed to carry four adults, and while each car's front seats are reasonably comfortable, those in the Cadillac are a bit too firm -- something we've noted previously in the CTS. The rear seat advantage also goes to BMW, which offers a touch more legroom and a slightly more comfortable bench. There is similar wheel well intrusion in each car's trunk and both offer average capacity.

At the dragstrip, the 328i pips the ATS by a full half-second to 60 mph, but that gap lessens to just 0.3 seconds through the quarter-mile, with runs of 14.1 and 14.4 sec, respectively. If you look at the charts for our two competitors, you'll see the cars are dead-nuts even to 15 and 30 mph, so why the big gap by 60 mph? Most of it has to do with the ATS' shorter gearing, which requires a second shift to get to the big six-oh. Around our figure-eight track, the race tightens. In fact, our cars managed identical 26.3-second laps -- a pretty amazing thing. Pure skidpad numbers give a 0.01 g advantage to the ATS and its wider rear rubber, and the Caddy also takes top braking honors, with a 108-foot stop from 60 to 0 mph, where the BMW required 113.

Too close to call? Not so fast. Though dimensions and performance specs may be nearly identical between our two sports sedans, there are marked differences in the way each car drives. Traditionally, one of the 3 Series' highlights has been its sharp, balanced handling and less compromised attitude. Ironically, it's here that the BMW is let down. We wouldn't call the 328i a poor-handling car by any stretch of the imagination, quite the contrary. Toss the BMW into a sharp turn, and mild initial understeer dissolves quickly to beautifully neutral behavior. A stab of the throttle will goad the rear into hanging out ever so slightly, but with utter control. The ride quality remains relatively supple; the downside is that the BMW has a slightly rubber sensation in relation to the ATS. Every input seems to be damped slightly; every corner entry just a hair slower; every sensation just that much more muted.

Take the same turn in the ATS and initial understeer is more abrupt, with more marked transitions to neutral, then slight oversteer under throttle provocation. But the inputs are sharper and the response is quicker. The steering has a directness that reminds us of the E46 3 Series, not the current car. We mean that in a good way. More than that, the chassis feels more responsive, firmer, tauter. The Caddy's engine feels punchier mid-range, and while the engine note isn't what you'd call melodic, it's a little louder and rawer. If the BMW is the Beatles, the Cadillac is the Rolling Stones. There's that much more aggression and drive to the ATS; that uncompromised driving experience that sadly no longer exists in the 3 Series. Drive the Bimmer without driving the Caddy and you may not even notice, but driven back to back, the difference is marked.

That's why the ATS' faults are so frustrating. We may have gotten a car with a defect, but the six-speed manual gearbox in our tester was hugely disappointing. Shifts were notchy and imprecise, with several testers continuing to miss gears even as hours in the car piled up. The transmission in the 328i is no sweetheart, but despite its rubbery feel, it didn't cause us to lose our concentration with botched gear changes.

The Caddy's suspension also needs some recalibration. The magnetic ride shocks have the potential to be brilliant, as we've seen in other GM products, but here they're tuned a tad too aggressively. There are two modes -- Normal and Sport -- and the latter is simply too firm to be used on any public road. We're also concerned about the damping rates in Normal mode, as there was some heavy and frankly unsettling up/down movement under certain conditions. We could pinpoint sections of road where this happened, but we couldn't quite explain why, given that the road surface was quite smooth. Simply put, it felt like the rebound rate may be too high, resulting in a somewhat violent bobbing motion.Those two faults are so significant in the driving experience that the BMW hangs on to win this comparison by the skin of its teeth and keep its segment crown. That said, we suspect GM will be doing what it can to remedy these issues post-haste. When it does, look out, BMW.

so, basically, the F30 is a faster in a drag race & the corners are close, so you tell me in a track, the coners will be close, then in the straights the 328i will pull, so since i dont see lap times, i take it the 328i will win with those facts alone... but also why auto... again with these cars like other have stated almost less than 10% will buy manuals.. so i will wait for the automatic comarison as well, & also, why test out the 328 vs the 2.0LT models.. where is the 335i vs the 3.6l comparo... im guessing you guys knew that the 335i will dominate the v6 ats as the 335i is known to be the best in its class right...?

What is with the fat guy doing the car comparison? He suck and his option does not amount to 2 cents. If that was bad enough he mumbles as if he has marbles in his mouth. Please Motor Trend do us a favor and keep this guy off camera!

I'd much prefer to see a comparison of the auto-trans loaded models. I now have a dodge caravan 3 door: it's my 4th red 3-door van, and I remain in love. Nevertheless, I would be open to looking at other options if the reviews are compelling enough.

I agree completely with Eco-boost-Carter's post. I'd much prefer to see a comparison of the auto-trans loaded models. I now have a BMW 335i Coupe: it's my 4th red 3-Series coupe, and I remain in love. Nevertheless, I would be open to looking at other options if the reviews are compelling enough.

What a stupid test. MT please post the sales numbers of manuals versus automatics, and then explain yourselves.My guess is less than 10% buy the manual trans anyways. Please set up a new comparo with the auto trannys, and then please include a whizbangery comparison as well. If I'm paying the same price, I damnwell better get the coolest tech.

I personally think the Volvo S60 is a better car than either of these two. Runs like a bat out of hell and a lot less money. And if it matters to anyone, it was one of only two cars to pass the latest crash tests.

Just remember, the Cadillac is junk. 5 years, 10 years from now, the BMW will still be solid, look great, be reliable and perform well. The Cadillac will be in the shop all the time, rattle like hell and drive down the road with a headlight or running light out or leave you stranded with all kinds of recurring electrical and mechanical problems. I've owned several GM products, and they were all junk.I have a 10 year old M3 and a 7 year old X5 which fit the above description of BMW. I'll take the rubbery feel and cheap knobs any day - car or woman (Did I say that?)

Personally, I am underwhelmed by both of these cars. That's not much performance for $45K+. There are better alternatives for the money(the Infiniti G37 comes to mind) and these cars couldn't have come out at a worse time. The Lexus IS, Infiniti G37 and Audi A4 will all be replaced soon. Adding to that, both Jaguar and Hyundai(laugh if you want, but they have the pieces and the current Genesis Coupe out-performs both the ATS and 3 Series) will be coming to the party as well. Both the ATS and 3 Series could be very dated by this time next year.

I love this ATS. They really pulled it off, they are actually over there together with the 3er: I think THIS is the news. The ATS is definitely better than A4 or C-class or S60. AND it's a Cadillac, a true American car even better refined than the bimmer. It's light and RWD. Great job, GM!

I can't get over the ATS's stupid headlights. But the rest of the design is nice, and I'm not really a fan of GM. It's unmistakably Cadillac. Would I buy one though? No, I'd much rather have the 3-Series. I just like the look of it more and I strongly prefer BMW's interiors over Cadillac's. (and any other interiors for that matter.) Would I recommend it to someone looking to buy a car in this class though? Yeah, it's a very good effort by GM after far too many years of less than stellar cars.

KZAK - I own a 2012 328i Sport Line 6mt; it came with Pirelli Cinturato P7 Summers as ALF mentioned. Also, the Sport line does get the sport suspension (w/ a 10mm lowering). The only thing the adaptive M suspension gives you is the option to go from sport to something softer.I think the BMW interior is just fine - and a big step up from the 9x series. Good quality materials, and BMW sport seats are very comfortable for long drives.I like both the ATS and the 328i; but I think based on the engine performance and 6MT alone, the ATS isn't quite there yet. But just barely.I love my 328i - it picks up well, corners well, and is rock solid at triple digit speeds. Was it expensive for the features I got? Yeah - but I knew that going in. I have no issue with Caddy building a 3 series beater - at least they had the balls and the motivation to do it. Otherwise, the choices were limited in the class. I have never been a fan of domestic cars, but I'd definitely look at an ATS the next time around.

Nothing against the caddy but you all should notice that BMW don't give you a sport suspension upgrade when you get the sport line unless you get the M sport package. The other important thing to note that the BMW rides on all-season tires while the Caddy is on summer ones

The real rival of the 328i is its big sister, the 335i. At 5.5 seconds to 60, it is nearly identical despite having 1 liter less capacity and 60 hp down (but I suspect it makes more than 240). The turbo four also proves to be more balanced because of the lighter engine. Economy is much better as well.But I have to give my applause to the ATS as well. It is a seriously fine effort that could soon topple the BMW from the top spot it's been hanging on to comfortably for several years now. Price is probably what will bring the Cadillac down. It is rather aggressive to come close to the Bimmer's sticker right away.

I confess I am surprised so many comment in favour of the ATS. It seems Cadillac has somehow hit the strings right this time. Still, I expect the average, mid-informed buyer will go for the sure thing, the more prestigious BMW.

My god the three series is terrible looking. That car looks so bad and it justs get worse on the inside. what a pathetic interior. If you'd ask me i'd rather take a infiniti G37 anyday over these two just because of the better interior. But if i were to choose between these two i definitely buy the caddy. The car looks elegant and beautiful.

Get somebody else to test these cars together and lets do this over with Auto trannies and see what happens! The front of that new 3 series is HORRID!!! BMW keeps coming out with bigger, fatter looking cars that look uglier and uglier each year! The interior of that 3 series looks the SAME as a late 90's E36 Bimmer! Really PATHETIC for the BMW price! No thanks...I'll go with the BETTER, AMERICAN MADE Cadillac ATS! AND stay tuned for an ATS-V series that completely wipes the floor with Bimmers just like the CTS-V does! :))

Its a strange day when a Cadillac looks better than a BMW. Its an even stranger day when the handling feels better. I'm just not sure where BMW is taking the 3 series. Still not sure I would buy a Caddy but its a decent effort and I know I wont buy an f30 3 series and if I HAD to choose I would take the Cadillac. The e46 and e90 are better looking and feeling to me. One question, why in the heck cant Cadillac get the shifter right? That is not a hard thing to fix or to get right. If they cant do it call any of the aftermarket shifter companies like hurst. Its a small part but has a major impact on driving.

RPIbaldum, Holden's performance cars are notorious for notchy manuals so I don't think they can help Cadillac too much.Cadillac has done a good job but I'd reckon resale values will favour the BMW hugely.

predictable outcome, the details really dont even matter. MR suspension is too firm? WOw, this is the ONLY review Ive seen that has made that claim. MR shocks have been universally praised in other reviews. As for the stick, the reality is few will buy it and the auto has been praised for its operation. Compare the auto versions of these cars or even the ATS 3.6 to the similarly priced 328i and see who wins. I sat in ATS today for first time, interior blows the dull 3 series away. The media is so in the bag for BMW that they wont tell it like it is because they can't slaughter the sacred cow. 3 series interior is slightly better than the Jetta and really no nicer than the Passat. There is nothing luxurious about it.

My co-worker just bought one. The transmission's feel is excellent, it is the gearing that could improve. Other then that, nice to see the media finally recognizing that there are better cars than the BMW. They are slow to recognize, but better late than never.And geez that BMW's dash looks dated & cheap... just like its external's look.

This is the written version of the video that came out 10 days ago, or so.They both have weak transmissions, and Caddy's is extra-bad. Sounds like BMW can be had, by the right product.Caddy is close, but not cigar, or synchro-mesh....BD

Tina, BMW's 3 series sales were down 17% last month so they should be losing sleep. As far as pricing goes, base prices are meaningless. You cannot find a $35K BMW on a lot and if you do it won't be very well equipped at all. The ATS 2.0T on the other hand comes with way more standard equipment for the price. If you do an apples to apples comparison the BMW is more expensive by several thousand. Plus, you get an inferior warranty (very important) with the BMW.

Wow that transmission in that ATS is horrible, I knew it was bad before reading but holy cow is that transmission utter garbage. And since when does Cadillac think they can pull off BMW prices? Hahaha..... Continue to lose no sleep BMW.

I'd certainly have to drive one of each, were I in the market for a sedan right now. Was this ATS's shifter quality anomalous or not? Can't own a car with a shoddy shifter. Wouldn't be prudent at this juncture.